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The North Atlantic Drives Shifts in Global Climate

The GWPF has a fascinating paper published recently which is attracting much attention. The author:

Anastasios Tsonis is distinguished professor of atmospheric sciences at the Universityof Wisconsin-Milwaukee. He is also an adjunct research scientist with the HydrologicResearch Center in San Diego.

It starts off talking about ENSO (El Nino/La Nina/Southern Oscillation) and how the frequency of these major modes of weather in the tropical pacific appears to be related to warming/cooling episodes. Basically, Tsonis notes that, as predicted by climate modeling, El Nino episodes appear to occur more often when the global climate is actively warming, and conversely, La Nina episodes predominate when cooling happens. This ties in with what Bob Tisdale has been saying for years, that El Nino events ‘step up’ global warming in discrete stages.

Tsonis identifies four distinct phases or global temperature regimes from the beginning of the 20th century: the 1910-1940s rapid warming, the 1960s cooling, the 1976-98 rapid warming and the ‘pause’ after 1998 (which bizarrely is not evident in the ‘pause-busting’ dataset which he chooses to illustrate the stages – GISS).

The author then goes on to talk about damped oscillating systems, e.g. a simple swinging pendulum and a spring-loaded pendulum. In the case of the simple pendulum, air resistance will eventually bring the pendulum to a predictable fixed position (i.e. at rest, pointing straight down, in line with the force of gravity), no matter from which position the pendulum is initially swung from. In the case of the spring-loaded pendulum, the predictable equilibrium position is not a fixed point but a limit cycle : the motion
is periodic and any fluctuation away from that limit cycle is damped back to the cycle. Such “systems with a fixed point or a limit cycle are said to have Euclidean attractors [equivalent to the equilibrium resting point or limit cycle] and they are predictable: the final state of the system can be known, regardless of the initial condition”. In the case of the climate, however, we have a highly non-linear system and an equilibrium position which is not at all easy to predict using a few simple equations: there is a degree of chaos at work within the system and the fractal determining which way the system will go is said to be a strange attractor. The system thus appears to be random but is in fact deterministic; it’s just that the outcomes are rather more complex to determine!

Tsonis goes on to identify four internal climate subsystems [ENSO, PDO, NAO and the North Pacific Index, NPI] which are associated with the strange attractors of the climate system. It turns out that the behaviour of these internal subsystems and in particular the ways in which these subsystems interact with one another is the key to determining how the system will evolve.

Tsonis then identifies two modes of interaction in operation between these subsytems: synchronisation and coupling. Imagine four swimmers: when they are all swimming in the same direction, doing the same stroke, at the same speed, they are synchronised, but independent. However, if a rope is tied around all their waists, they are physically constrained to move non-independently and are said to be coupled.

Now, as Tsonis explains:

The theory of synchronised chaos predicts that in many cases when such systems synchronise, an increase in coupling between the oscillators may destroy the synchronous state and alter the system’s behaviour.

This principle applies equally in the climate system. Coupling tends to disrupt synchronisation and propel the system abruptly into a new state. Tsonis illustrates the main periods of synchronisation and coupling present in the instrumental global surface temperature data:

As you can see, coupling occurs at the junctures of major shifts in climate: the commencement of 1910-1940s warming; the start of the mid-century cooling period; the re-commencement of rapid warming post 1976, and the pause after 1998. Tsonis says of these shifts:

This mechanism appears to be intrinsic to the climate system: it is found in both control and forced climate simulations. It also appears to be a very robust mechanism. In all 13 synchronisation events found in the observations and model simulations, when the modes are synchronised and the coupling begins to increase, then at some coupling strength threshold synchronisation is destroyed and the system shifts to a new state.

Thus the author appears to have identified a robust predictor of when changes in climate will occur, simply by examining four different modes of internal variability and their interactions. Now, pay attention please, because this is where it gets really interesting. Tsonis asks the question:

When the network is synchronised, does the coupling increase require that all modes must become coupled with each other? To answer these questionsWang et al. split the network of four modes into its six component pairs and investigated the contribution of each pair during each synchronisation event and in the overall coupling of the network. They found that one mode is behind all climate shifts. Surprisingly, the mode concerned is not ENSO but the NAO: it is, without exception, the common ingredient in all shifts in the climate regime and when it is not coupled with any of the Pacific modes no shift ensues . . . . .

Thus, the results indicate not only that NAO is the instigator of climate shifts but that the likely evolution of a climate shift has a path in which the north Atlantic couples to the north Pacific, which in turn couples to the tropics. [my emphasis].

The NAO of course, is a reasonable proxy measure of the AMO/AMOC, and numerous studies indicate a connection between solar variability (in particular solar UV variability) and NAO (e.g., whether it is predominantly positive of negative during northern hemisphere winters). So, all things considered (AMO peaking and turning negative, solar activity declining rapidly, perhaps to a new grand solar minimum), it looks very much like a major shift in climate is due very soon. Of course, this may be a recommencement of rapid warming, but I wouldn’t throw too much money into climate hedge funds along the lines of that particular scenario happening.

Thanks for digging into this interesting paper. The notion of independent actors sometimes synchronizing and even coupling explains our difficulties untangling the mechanisms driving climate fluctuations.
I was alerted to the example of a double pendulum (a slight variation on Tsonis’ point) I will try to post the diagram and some explanation: Trajectories of a double pendulum

A comment by tom0mason at alerted me to the science demonstrated by the double compound pendulum, that is, a second pendulum attached to the ball of the first one. It consists entirely of two simple objects functioning as pendulums, only now each is influenced by the behavior of the other.

Lo and behold, you observe that a double pendulum in motion produces chaotic behavior. In a remarkable achievement, complex equations have been developed that can and do predict the positions of the two balls over time, so in fact the movements are not truly chaotic, but with considerable effort can be determined. The equations and descriptions are at Wikipedia Double Pendulum

But here is the kicker, as described in tomomason’s comment:

If you arrive to observe the double pendulum at an arbitrary time after the motion has started from an unknown condition (unknown height, initial force, etc) you will be very taxed mathematically to predict where in space the pendulum will move to next, on a second to second basis. Indeed it would take considerable time and many iterative calculations (preferably on a super-computer) to be able to perform this feat. And all this on a very basic system of known elementary mechanics.

Ron, that’s a very fine example of a coupled ‘quasi-chaotic’ system. Really quite hypnotic watching it! What’s interesting is that by coupling the pendulums, the degrees of freedom of each is actually increased rather than, as one might expect, restricted.

Ron Clutz
The Tomomason quote “If you arrive to observe…” seems to be a translation from French (“arriver à..” = “manage to..”.) Where’s it from?
Your double pendulum is fascinating. Even a mathematical ignoramus like me can spot the constraints, the gravity effect, the tendency to pass through the centre.. There must be some similar thingy that could move along an x axis, constrained not to go left of the fixed point, moving rightwards in unpredictable zigs and zags. I wonder what it would look like?

Continuing from that point, this explains why weather models are unreliable beyond about 10 days, and why climate models have no “lift” over statistical history after 10 years. R.G. Brown of Duke explained it clearly a few years ago in a comment I reposted here:https://rclutz.wordpress.com/2015/06/11/climate-models-explained/

Some simple points. The Planck response is 3.2W/m^2/K. You can even approximate this quite easily from some fairly basic physics. This means that if the surface warms by about 1K, then in the absence of any other changes, we will be radiating an extra 3.2W/m^2 into space. The heat capacity of the upper ocean (top 50m say) and the atmosphere is about 10^23J/K (i.e., it takes about 10^23 J to heat it by 1K). If we increase the outgoing flux by 3.2 W/m^2 then that means we will be losing about an extra 5×10^22 J per year. In other words, in the absence of any other change, an increase of 1K will be associated with an increase in energy that we would radiate back into space in about 2 years. All of this has been done on my laptop’s calculator, which is irritating to use, so there may be some silly error, but I think it is roughly correct.

The key point, though, is that you cannot produce a long-term increase in surface temperature without something else in the atmosphere changing so as to reduce the outgoing flux. Without the latter, any temperature enhancement will be lost in a matter of years, or less. The only way that a temperature enhancement can be sustained is via some change to the radiative properties of the atmosphere. It could be some kind of response to the temperature change (i.e., clouds, water vapour etc). However, if you want to argue this, then you also have to explain why it responds to naturally-driven warming, but not to anthropogenically-driven warming and this – as far as I can tell – is an extremely tricky argument to make since there’s no reason why there should be any real difference in the response.

Natural warming results from a change in the proportion of external insolation reaching the surface so as to enable absorption by the oceans.
That effectively mimics an increase in external insolation.
Radiative capabilities of constituent gases do no such thing. Consequently such radiative effects are neutralised by convective circulation changes otherwise hydrostatic balance would be destroyed and the atmosphere would be lost.
Thus human induced changes or natural changes in radiative effects are both dealt with in the same way via circulation changes instead of changes in average surface temperature.
The circulation changes from our contribution would be too small to measure compared to natural solar and oceanic changes.

“It could be some kind of response to the temperature change (i.e., clouds, water vapour etc)”.

Then again, it could be the surface temperature response to increases or decreases in clouds, water vapour etc. Tropical cloud cover declined significantly from the 1980s to 1998, allowing, presumably, more SW solar energy to penetrate the tropical oceans, thus warming them, which increased ocean heat, presumably, was distributed effectively around the globe via enhanced El Nino cycles, which, presumably, may account for a significant fraction of the increase in global mean surface temperature over that period. There is no reason to presume that this decline in tropical cloud cover was in response to surface warming. In fact it makes more sense in my opinion to view it as part of an ongoing natural cycle of change brought about by changes in global circulation patterns linked to internal modes of variability.

Jaime and Stephen, to your points about changing amounts of insolation through the atmosphere, there is confirmation from Institute for Atmospheric and Climate Science of ETH Zurich, led by Martin Wild, senior scientist specializing in the subject. They are a leading center for global brightening/dimming research. Observed tendencies in surface solar radiation:
Figure 2. Changes in surface solar radiation observed in regions with good station coverage during three periods.(left column) The 1950s–1980s show predominant declines (“dimming”), (middle column) the 1980s–2000 indicate partial recoveries (“brightening”) at many locations, except India, and (right column) recent developments after 2000 show mixed tendencies. Numbers denote typical literature estimates for the specified region and period in W m–2 per decade. Based on various sources as referenced in Wild (2009).

The latest updates on solar radiation changes observed since the new millennium show no globally coherent trends anymore (see above and Fig. 2). While brightening persists to some extent in Europe and the United States, there are indications for a renewed dimming in China associated with the tremendous emission increases there after 2000, as well as unabated dimming in India (Streets et al. 2009; Wild et al. 2009).

We cannot exclude the possibility that we are currently again in a transition phase and may return to a renewed overall dimming for some years to come.

Thanks for that link Ron. An excellent summary of what we know – and, more importantly, what we don’t know – about clouds, aerosols and aerosol-cloud interactions and their effects upon surface temperature via ‘brightening’ and ‘dimming’. I’ve never been particularly convinced by the anthropogenic aerosols explanation for mid 20th century cooling, so I’m bound to quote this:

“Analysis of the Angstrom-Prescott relationship between normalized values of global radiation and sunshine duration measured during the last 50 years made at five sites with a wide range of climate and aerosol emissions showed few significant differences in atmospheric transmissivity under clear or cloud-covered skies between years when global dimming occurred and years when global brightening was measured, nor in most cases were there any significant changes in the parameters or in their relationships to annual rates of fossil fuel combustion in the surrounding 1° cells. It is concluded that at the sites studied changes in cloud cover rather than anthropogenic aerosols emissions played the major role in determining solar dimming and brightening during the last half century and that there are reasons to suppose that these findings may have wider relevance.”

Also, from Tsonis’ paper:

“In the past, this decadal variability was ‘modeled’ as a tug-of-war between aerosols and carbon
dioxide effects. The argument was that in times when aerosols were ‘winning’, the Earth would cool, while in times when carbon dioxide effects were more dominant, the Earth would warm. The results presented here refute this arbitrary assumption as they demonstrate that a dynamical mechanism is responsible for climate shifts.”

I studied the Tsonis paper with great interest when GWPF first published it. I have some significant reservation about parts of it. The underlying observational ocean systems are ENSO, PDO, AMOC, and NAO.
General records of ENSO go back centuries, although instrumented central Pacific water temps go back only several decades. First observed centuries ago related tothe Chilean anchovie harvest.
NAO was ‘discovered’ in several papers late 19th-early 20th centuries. So about a century of data.
But the AMOC was first reported in 1957, so only half century of data.
And the PDO,was first reported in 1996, discovered accidentally by studying the Pacific Northwest US salmon fisheries. So essentially only two decades of data.
I don’t think either AMOC or PDO provide long enough observational time series to describe the oscillations of warming and cooling. Warming ~1920-1945, slight cooling ~1945-1975, warming ~1975-2000, no warming since. A roughly 30~35 year half cycle, so ~60-70 year full cycle. Tsonis ignores the Nyquist sampling theorem. So IMO is merely a speculation at this point.

“The key point, though, is that you cannot produce a long-term increase in surface temperature without something else in the atmosphere changing so as to reduce the outgoing flux. Without the latter, any temperature enhancement will be lost in a matter of years, or less. The only way that a temperature enhancement can be sustained is via some change to the radiative properties of the atmosphere.”

Nice to find you in a comment field where you can´t edit my posts to censor out uncomfortable questions.

Are you saying that a cold fluid, heated by a warm solid heat source, can increase the temperature of the heat source heating the cold fluid?

Another uncomfortable question for you:

Prevost, one of the pioneers of thermodynamics, said that the emission from a body depends on the internal state, only. It has not been questioned that he was correct. It is the foundation of thermodynamics and blackbodies, the emitted heat from a solid body, depends only on the internal state. The internal state is proportional to the emissive power, which we measure as temperature.

If the emission from a solid body (earth) depends ONLY on the internal state, why do you claim that the temperature at the surface depends on the external state of the atmosphere?

Why are you denying the science of heat engines? Do you think that we should ignore the only 100% consensus science that exists, thermodynamics?

Btw, the north atlantic drives nothing. There are two glowing bodies involved, they are the sources of energy. They drive everything. Everything we see on the surface are effects, nothing is a cause. The sun and the hot internal earth is what drives the whole climate system, because heat only moves from hot to cold. The oceans are coolers and we see the effects there, not the causes.

It was me who mentioned AMOC. Tsonis’ climate indices are Pacific Decadal Oscillation (PDO), the NAO, ENSO, and the North Pacific Index (NPI). As regards PDO, even though it was ‘discovered’ in 1997, I think its signal can be fairly reliably traced backwards in the instrumental and proxy records.

The first figure seems to show quite clearly that there was no change in1998. Since the study apparently finds a change there, using that data, when there clearly is none, it’s hard to see why anyone would bother with it any further.

Are you saying that a cold fluid, heated by a warm solid heat source, can increase the temperature of the heat source heating the cold fluid?

Don’t know if I’m saying this, but let’s imagine the following. Consider a system with some heat source (a room with a radiator, for example). If you turn on the heat source then it will add energy to the system and the temperature of the system will go up. The temperature to which it will settle will be the temperature at which it is losing energy to the external environment at the same rate as energy is being added. Now enclose that system in some kind of insulator that reduces the rate at which it loses energy to the external environment. The temperature will, typically, go up until the rate at which it is losing energy to the environment again matches the rate at which energy is being added. This will happen even if we don’t change the rate at which energy is being added.

This is essentially what our atmosphere is doing. In a simple sense (it is a bit more complex than this) the surface gets energy from the Sun and the atmosphere acts to reduce the rate at which the surface loses energy to space. This cause the surface temperature to be higher than it would be in the absence of an atmposphere (all else being equal).

That ignores the dynamic nature of a gaseous insulator that has no fixed volume.
Applying the gas laws the resulting changes in the convective circulation neutralise the thermal effect of radiative imbalances.
Since solar and oceanic variability already wreak huge changes in circulation we could never observe the effect on atmospheric circulation from our emissions.